The History of the Decline and Fall of the Roman Empire, Volum 1

From the middle of the second century CE, The Roman Empire faced increasing Germanic tribe infiltration along the Danubian and Rhine borders, and internal political chaos. Without efficient imperial succession, Romans in from the third century set up generals as emperors, who were quickly deposed by rival claimants. Facilitating further territorial losses to Barbarian tribes, this continued until Diocletian (r. 284-305). He and Constantine (324-337) administratively reorganized the empire, engineering an absolute monarchy. Cultivating a secluded imperial tenor, Constantine the Great patronized Christianity, particularly in his new city Constantinople, founded on the ancient site of Byzantium. Christianization, in the Hellenized and Mediterranean cities and among certain Barbarian newcomers, proceeded with imperial support, and became the state religion under Theodosius (r. 379-95).